1. Field of the Invention
The present invention relates generally to motor vehicles, and in particular the present invention relates to a solid engine mount suitable for use with motor vehicles.
2. Description of Related Art
The power train of a motor vehicle generates motions that can be discerned by the passengers of the motor vehicle as Noise, Vibration, and Harshness (NVH). The support provided by the power train mounting system is used to improve NVH by absorbing or resisting the motion of the power train. The mounting system attaching the power train to the motor vehicle frame generally provides a response to the vertical, horizontal, and torque motion of the power train to absorb the motions of the power train and to minimize the transfer of those vibrations and their effects such as NVH to the passenger compartment of the motor vehicle.
The related art teaches a variety of features and functions related to mounting systems for attaching a power train to a motor vehicle.
U.S. Pat. No. 6,547,207 to Thompson teaches a motorcycle engine mount with an elastomeric member with a central cavity. The elastomeric member is sandwiched between metal plates. The elastomeric member is generally cylindrical, not frustoconical, in shape. Further, the ends of the elastomeric member are not free, as one of the metal plates rests flush against one end of the elastomeric member, while the other end of the elastomeric member is fitted to an interior surface of the other metal plate. Additionally, the sides of the Thompson elastomeric member are not covered by a metal housing.
U.S. patent application publication No. 2003/0107163 to Asano et al. teaches a vibration isolation bushing with an elastomeric body positioned between an inner cylinder and an outer cylinder. The inner cylinder defines the central bore. However, Asano et al. does not teach the use of a solid elastomeric body, as several axial bores are formed in the elastomeric body in addition to the central bore. These axial bores give the Asano et al. elastic body a frustoconical shape in cross-section. The frustoconical shapes in the Asano et al. mount are orthogonal to the central bore through the mount. Further, the small ends of the frustoconical shapes in the Asano et al. mount are constrained by the metal housing of the mount.
U.S. Pat. No. 3,836,100 to Von Hardenberg et al. teaches placing a front mount of a helicopter engine and a rear upper mount on the horizontal line of restraint passing through the center of gravity. The rear upper mount has significant lateral stiffness, but near zero vertical stiffness. A rear lower mount has significant vertical stiffness, but near zero lateral stiffness. This arrangement decouples the engine roll response from frame lateral input motion.
DE patent number 4009995 to Edison et al. teaches using two static mounts to define a roll axis having low stiffness in the roll direction. A lateral mount provides significant stiffness orthogonal to the roll axis, but also includes a decoupled dampener to provide soft, dynamic response to isolate engine vibrations about the roll axis during idling.
While the related art teaches a number of different mounts and torque roll axis features due to placement of the mounts, what is needed is a solid engine mount with the axial stiffnesses optimized for NVH characteristics. Also needed is a power train mounting scheme that positions the power train roll center at or near the power train center of gravity to optimize NVH characteristics.